Lubricant and method of preparing same



Patented Jan. 20, 1942 Eugene Lieber, Staten Island, N. Y., assignor to Standard Oil Development Company, a corporation of Delaware No Drawing. Application July 16, 1940, Serial No. 345,856

' 5 Claims. (Cl. 252-56) The present invention relates to improvements in lubricants and methods of preparing same, and more broadly to various wax-containing compositions into which a wax modifier is incorporated in order to modify the crystal structure of the wax.

It has now been found that the substance called tall oil, which isa by-product obtained in the manufacture of paperfrom pine wood, has wax modifying properties. Accordingly, the primary object of this invention is to incorporate a small amount of this tall oil into waxy mineral lubricating oils to reduce the pour points thereof.

Another object is to use a small amount of tall oil as a separation aid in the process of .dewaxing oils. These and other objects and advantages of the invention will be understood more clearly from the following specification.

Tall oil is a product recovered from sulfide liquor waste of the paper industry. It is an organic product, a mixture of acids, esters and non-U saponifiable varying in composition from time to time depending principally upon the source of the pine wood from which it is made and on the details of the method of preparation and refining. Ordinarily, the acid number of such a product is from 110 to 170, the saponification number from about 125 to 190 and the iodine number is usually from about 100 to 130. The

product contain resin acidswhich, however, dif- Percent content in Constituent Crude Distilled Rosin acids 58 35 Fatty acids i r 18 50 Non acids (stcrol, etc.) 24 15 In the above discussion, the term rosin acids is intended to mean those acids which do not esterify with methyl or ethyl alcohol after boiliii ing for a few minutes in the presence oi'sulfuric acid.

The present invention is considered very important from a commercial and practical point of view because the amount of tall oil available in the United States alone is tremendous, probably about 75,000 or 100,000 tons annually, and since it is a by-product of the paper pulp industry it is available at relatively low cost.

In carrying out the present invention, atsmall amount of tall oil is merely dissolved in the waxy mineral lubricating oil or other wax-containing compositions in which it is intended that the tall oil should serve as wax modifiers. To serve as a pour depressor in waxy mineral lubricating oils, the amount of tall oil to be used should usually be within the approximate limits of 0.1% to 10.0%, generally from about 0.5% to 5.0%, depending upon the relative pour depressor potency of the particular tall oil sample being used, and upon the pour depressor requirements of the lubricating oil base stock being used, and upon the degree of pour point reduction desired.

Although it is preferred to use a refined or at least semi-refined tall oil, such as one marketed under the trade name of Liqro, it is also possible to use the crude or refined product such as may be obtained by distillation, solvent extraction or other separation methods, in order to make use of the particular fraction or fractions which are richest in the active pour depressor principle.

The lubricating oil base stock which may be improved by th addition of tall oil thereto, according to the present invention, may be any natural or synthetic lubricating oil or fraction thereof containing a sufficient amount of con-' stituents of a waxy nature to impart to the oil an undesirably high pour point (as determined by the standard A. S. T.. M. method). These lubricating oil stocks may be obtained from various types of crude such as the parafl'inic Pennsylvania type or naphthenic or mixed base crudes, etc. such as the Mid-Continent, Coastal, Venezuela, etc., but the invention applies particularly to lubricating oil stocks which are especially rich in parafllnic constituents. Such fractions may be obtained from fractions which are low in paraifinic constituents by various methods such as by solvent extraction with solvents which remove the non-parafiinic constituents or by bydrogenation or by any other suitable means. Instead of using single oils or fractions thereof, various mixtures or blends may be used as is well known in the art, as, 'for instance. a small amount of bright stock may be mixed with a larger amount of a lower viscosity neutral oil.

The following experimental data will illustrate the eii'ectiveness of the present invention:

Example 1 2% by weight of a semi-refined tall oil known under the trade name of Liqro was added to a commercial lubricating oil having a pour point of +15 F, The blend was found to have a pour point of F., thus showing that 2% addition of the tall oil effected a 15 reduction in pour point.

Example 2 2% by Wight of Liqro was added to a blend consisting of 90% by volume of Manchester spindle oil and by volume of bright stock, this original 'blend having a pour point of +30 F. The addition of the tall oil reduced the pour point to 20 F.

Example 3 "Liqro" was subjected to high vacuum distillation until 10% by volume was removed as an overhead distillate. 2% of the distillation bottoms so obtained was blended into the same test oil as Example 2. A pour point of +10 F. was obtained.

The invention is even the more remarkable due to its simplicity and economy because heretofore commercial pour depressors have been made by a relatively expensive chemical condensation process such as, for instance, the condensation of chlorinated paraflin wax with naphthalene. It is obvious that this prior art process necessitates the use of three raw materials, namely, paraffin wax, chlorine and naphthalene, and two chemical treatments, namely, the chlorination of the wax and the condensation of the chlorinated wax with the naphthalene, with the further consideration that a small amount of aluminum chloride must be used as catalysts. The present invention avoids these various complications by using a single raw material without any chemical treatment whatsoever, since the tall oils, both crude and in various stages of refinement, are already commercial products on the market.

It is not intended that this invention be limited to the specific examples which have been Per cent Rosin acids 35 Fatty acids"--- Non-acids (sterol, etc.) l5

4. A low pour lubricant consisting essentially of a waxy mineral lubricating oil base stock having a pour point between the approximate limits of +15 F. and +30 F., and a pour-depressing amount, between the approximate limits of 0.5% and 5.0%. of tall oil.

5. A lubricant comprising a major proportion of a waxy mineral lubricating oil and a pourdepressing amount of a fraction relatively rich in pour-depressing properties separated from crude tall oil.

EUGENE LIEBER. 

